Disclosure of Invention
In order to solve the technical problems that a volume array form adopted by an aviation hoisting sonar in the related art is high in beam main lobe, wide in side lobe and poor in performance when conventional beam forming is carried out, the application provides a beam forming method and device based on the aviation hoisting sonar. The specific technical scheme is as follows:
in a first aspect, a beam forming method based on aerial sonar lifting is provided, and the method includes:
after the volume array sonar rotates for the preset angle for the kth time, acquiring a receiving signal of an outer arm array element and a receiving signal of an inner arm array element of the volume array sonar;
converting real signals received by the outer arm array element and the inner arm array element of the volume array sonar into complex signals;
constructing a virtual array element signal according to the complex signal and the estimated expected signal;
calculating a combined signal according to the complex signal and the virtual array element signal;
performing delay summation calculation on the combined signal to obtain a weight vector of the combined signal;
and calculating the combined signal according to the weight vector to obtain a beam forming signal corresponding to the volume array sonar after the volume array sonar rotates for the predetermined angle at the kth time.
Optionally, the real signal that receives volume array sonar outer arm array element and inner arm array element is converted into complex signal, include:
and respectively filtering real signals received by the outer arm array element and the inner arm array element of the volume array sonar by using a Hilbert filter so as to convert the real signals into complex signals.
Optionally, after the combined signal is calculated according to the weight vector to obtain the beam-forming signal, the method further includes:
and rotating the volume array sonar by a preset angle for the (k + 1) th time, continuing to execute the step of acquiring the receiving signals of the outer arm array elements and the receiving signals of the inner arm array elements of the volume array sonar until the volume array sonar completes one rotation, and combining the beam forming signals obtained after each rotation to obtain a combined signal beam forming directional diagram.
The beam forming method provided by the application determines the virtual array element signals according to the array element receiving signals of the outer arm and the inner arm of the volume array sonar, the beam main lobe of a conventional beam forming algorithm obtained by utilizing the virtual array element signals is narrower, meanwhile, the side lobe is lower than that of conventional array beam forming, and the performance is greatly improved.
In a second aspect, a beam forming device based on aerial sonar lifting is provided, the device includes:
the receiving signal acquisition module is configured to acquire a receiving signal of an outer arm array element and a receiving signal of an inner arm array element of the volume array sonar after the volume array sonar rotates for a preset angle for the kth time;
the conversion module is configured to convert real signals received by the outer arm array element and the inner arm array element of the volume array sonar into complex signals;
the construction module is configured to construct a virtual array element signal according to the complex signal obtained by the conversion module and the estimated expected signal;
the computing module is configured to compute a combined signal according to the complex signal obtained by the conversion module and the virtual array element signal obtained by the construction module;
the weight vector acquisition module is configured to perform delay summation calculation on the combined signal obtained by the calculation module to obtain a weight vector of the combined signal;
and the beam synthesis signal acquisition module is configured to calculate the combined signal obtained by the calculation module according to the weight vector obtained by the weight vector acquisition module to obtain a beam synthesis signal corresponding to the volume array sonar after the volume array sonar rotates for the predetermined angle for the k time.
Optionally, the conversion module is further configured to:
and respectively filtering real signals received by the outer arm array element and the inner arm array element of the volume array sonar by using a Hilbert filter so as to convert the real signals into complex signals.
Optionally, the apparatus further comprises:
and a directional diagram acquisition module configured to rotate the volume array sonar by a predetermined angle (k +1 th time), trigger the received signal acquisition module 401 to continue to perform the steps of acquiring the received signals of the outer arm array elements and the received signals of the inner arm array elements of the volume array sonar until the volume array sonar completes a rotation for one circle, and combine the beam-forming signals obtained after each rotation to obtain a directional diagram formed by combining the beams of the combined signals.
The utility model provides a beam forming device confirms virtual array element signal according to the array element received signal of volume array sonar outer arm and inner arm, and the wave beam main lobe of the conventional beam forming algorithm that utilizes virtual array element signal to obtain is narrower, and the side lobe is lower than the side lobe of conventional array beam forming simultaneously, and the performance has very big promotion.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.
Fig. 1 is a flowchart of a beam synthesis method based on an aerial lift sonar according to an embodiment of the present application, where the beam synthesis method based on an aerial lift sonar includes:
step 101, after the volume array sonar rotates for the predetermined angle for the kth time, acquiring a receiving signal of an outer arm array element and a receiving signal of an inner arm array element of the volume array sonar at the time of the kth time;
in order to acquire signals at different angles and calculate by utilizing signals at multiple angles to obtain synthesized beams, a volume array sonar is adopted in the application. Generally, the number of extension arms of a volume array sonar is N, the number of inner arm array elements is the same as that of outer arm array elements, and the array element spacing between the inner arm array elements and the outer arm array elements is 0.5 times of half wavelength (i.e. d is λ/4), then the received signals of the outer arm array elements and the inner arm array elements at the kth time can be respectively expressed as:
xA(k)=[x1(k) x2(k) ... xN(k)]
xB(k)=[xN+1(k) xN+2(k) ... x2N(k)]
wherein N is a natural number, and k is 1,2.
In order to obtain the combination of the beam-forming signals corresponding to each angle of the volume array sonar and determine the corresponding directional diagram of the combined signal beam-forming, the volume array sonar is sequentially rotated by a preset angle in the application, and the k time can be used for indicating the corresponding rotation sequence when the volume array sonar rotates for the k time.
For example, please refer to fig. 2, which is a schematic diagram of a vertical distribution of a 24-element volume array provided in an embodiment of the present application, where the number of extension arms of a volume array sonar is 12, the numbers of outer arm array elements are 1 to 12, respectively, and the numbers of inner arm array elements are 13 to 24, at a kth time, a received signal of an outer arm array element of the volume array sonar may be represented as:
xA(k)=[x1(k) x2(k) ... x12(k)]
the received signal of the inner arm array element of the volume array sonar can be expressed as:
xB(k)=[x13(k) x14(k) ... x24(k)]
102, converting real signals received by an outer arm array element and an inner arm array element of the volume array sonar into complex signals;
optionally, real signals received by the outer arm array element and the inner arm array element of the volume array sonar may be filtered by hilbert filters, so as to convert the real signals into complex signals.
For example, the outer arm array elements are connectedReceived real signal xA(k)=[x1(k) x2(k) ... xN(k)]The converted complex signal is:
sA(k)=[s1(k) s2(k) ... sN(k)]
for example, the real signal x received by the inner arm array elementB(k)=[xN+1(k) xN+2(k) ... x2N(k)]The converted complex signal is:
sB(k)=[sN+1(k) sN+2(k) ... s2N(k)]
103, constructing a virtual array element signal according to the complex signal and the estimated expected signal;
constructing a virtual array element signal according to a complex signal obtained by converting received signals of an outer arm array element and an inner arm array element of the volume array sonar and an estimated expected signal theta, wherein the virtual array element signal comprises the following components:
step 104, calculating a combined signal according to the complex signal and the virtual array element signal;
in a possible implementation manner, according to the complex signal and the analyzed virtual array element signal, the calculated combined signal is:
105, performing delay summation calculation on the combined signal to obtain a weight vector of the combined signal;
the weight vector of the combined signal is obtained according to the delay-sum beam forming algorithm
Wherein
θ
iIs the angle between the ith receiving arm and the X axis, r ═ r
A+r
B) A/2 isRadius of the virtual array element.
Step 106, calculating the beam forming signal at the k-th time
The k-th time from step 101 to step 106 corresponds to a certain rotation angle of the volume array sonar, and when the volume array sonar is rotated by a predetermined angle again, the beam forming signal corresponding to the k + 1-th time is calculated.
Step 107, judging whether the volume array sonar finishes rotating for one circle;
when the volume array sonar does not rotate for a full circle, continuing to execute the step 108; when the volume array sonar rotates for one circle, the Beam synthesis signals obtained from all angles are combined to obtain a directional diagram Beam of the Beam synthesis of the combined signal [ Beam (t) ]0) Beam(t1) ... Beam(tM)]。
And 108, when the volume array sonar rotates less than one week, continuing to rotate the volume array sonar by a preset angle, and executing the step 101.
That is, the volume array sonar rotates at a constant speed for one circle, the above steps 101 to 106 are repeatedly executed every predetermined angle to obtain the Beam-forming signals corresponding to the current angle, and then the Beam-forming signals obtained at each angle are combined to obtain a Beam-forming pattern Beam of the combined signal [ Beam (t) is0) Beam(t1) ... Beam(tM)]。
The directional diagrams obtained by respectively calculating the conventional array beam forming algorithm and the virtual array method by using the conventional beam forming algorithm (i.e., by using a delay weighting method) are shown in fig. 3, and are based on 24-array sonar, and the directional diagrams obtained by using the conventional beam forming method and the virtual array beam forming method are used under the condition that the incident angle of the expected signal is 0 °. As can be seen from fig. 3, compared with the conventional beam synthesis method, the beam main lobe of the conventional beam forming algorithm obtained by using the virtual array element method is narrower, and meanwhile, the side lobe is lower than that of the conventional base array beam forming, so that the performance is greatly improved.
In summary, according to the beam forming method based on the aerial sonar of hanging up and releasing, the beam main lobe of the conventional beam forming algorithm obtained by using the method of the virtual array element is narrower, meanwhile, the side lobe is lower than that of the conventional array beam forming, and the performance is greatly improved.
The following are embodiments of the disclosed apparatus that may be used to perform embodiments of the disclosed methods. For details not disclosed in the embodiments of the apparatus of the present disclosure, refer to the embodiments of the method of the present disclosure.
Fig. 4 is a schematic structural diagram of a beam forming apparatus based on aerial sonar lifting system according to an embodiment of the present application, where the beam forming apparatus implements the beam forming method through software, hardware, or a combination of software and hardware. This beam forming device based on sonar is put to aviation includes:
a received signal acquiring module 401 configured to acquire a received signal of the outer arm array element and a received signal of the inner arm array element of the volume array sonar;
a conversion module 402 configured to convert real signals received by the outer arm array element and the inner arm array element of the volume array sonar into complex signals;
a constructing module 403 configured to construct a virtual array element signal according to the complex signal obtained by the converting module 402 and the estimated expected signal;
a calculating module 404 configured to calculate a combined signal according to the complex signal obtained by the converting module 402 and the virtual array element signal obtained by the constructing module 403;
a weight vector obtaining module 405 configured to perform delay summation calculation on the combined signal obtained by the calculating module 404 to obtain a weight vector of the combined signal;
and a beam synthesis signal acquisition module 406, configured to calculate the combined signal obtained by the calculation module according to the weight vector obtained by the weight vector acquisition module 405, so as to obtain a beam synthesis signal corresponding to the volumetric array sonar after rotating by the predetermined angle for the k time.
Optionally, the conversion module 402 is further configured to: and respectively filtering real signals received by the outer arm array element and the inner arm array element of the volume array sonar by using a Hilbert filter so as to convert the real signals into complex signals.
Optionally, the apparatus further comprises:
and the directional diagram acquisition module is configured to rotate the volume array sonar by a preset angle for the (k + 1) th time, trigger the received signal acquisition module 401 to continue to execute the step of acquiring the received signals of the outer arm array elements and the received signals of the inner arm array elements of the volume array sonar until the volume array sonar completes a rotation for one circle, and combine the beam synthesis signals obtained after each rotation to obtain a directional diagram synthesized by the combined signal beams.
To sum up, the beam forming device based on the aerial sonar of hanging up and releasing provided by the application utilizes the method of the virtual array element to obtain a narrower beam main lobe of a conventional beam forming algorithm, and meanwhile, the side lobe is lower than that formed by the conventional array beam, and the performance is greatly improved.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.